The coupler is a functional component located at both ends of a locomotive or car and has a standard connecting contour. The coupler is used to achieve the coupling between locomotives or cars and transmit a longitudinal force (e.g. traction force or compression force).
At present, the automatic coupler is widely used in railcar, and mainly consists of three parts, i.e., coupler head, coupler shank and coupler tail. Some parts such as coupler knuckle, coupler knuckle lock, knuckle thrower, coupler knuckle pin and lower lockpin mechanism are installed in a cavity of the head of the coupler shank. The lower lockpin and a lower lockpin rod are hinged by rivet to form a lower lockpin mechanism. Two cars may be coupled with each other spontaneously when they are colliding, and a coupler lifting bar may be manipulated from outside to achieve the separation between coupled cars, so as to improve the operating efficiency in train marshalling and ensure the safety of operator. Conventional automatic coupler will be operated in three operating states, i.e., locked state, unlock state and full open state. Whether the coupler may be maintained well in three operating states in use is one of the important indexes for evaluating the safety and reliability thereof. When the coupler is in the locked state, a coupler knuckle lock stops a coupler knuckle from being opened and coupled cars cannot be separated spontaneously. When rotating the coupler lifting bar, the coupler knuckle lock is slightly lifted to the unlock position, and then the coupler is switched into the unlock state. The coupler knuckle will be opened under external force and separate cars. When the coupler lifting bar is rotated to the upmost position, the coupler knuckle is pushed to a full open position by the coupler knuckle lock and knuckle thrower. At this time, the coupler is switched into the full open state, and adjacent cars are prepared for coupling.
In various operating conditions, the coupler knuckle lock might be moved away from the coupler knuckle locking surface under gravity due to vibration and impaction and thus the coupler is in the unlock state, or the lower lockpin mechanism might be rotated due to the vibration of car and drive the coupler knuckle lock to move upwardly to the unlock position, thereby accidentally unlocking the coupler. As well known, such abnormal unlocking of the coupler will result in accidents such as separation between cars and abnormal parking of car, which seriously affects the normal transportation in the railway. Therefore, in order to improve the transportation efficiency and safety in the railway, it is very important to prevent the coupler from being abnormally unlocked.
In order to prevent the coupler from being abnormally unlocked, conventional automatic coupler is provided with an anti-creep mechanism. The lower lockpin rod and the coupler shank are hinged through a rotation shaft 30. In normal operating state, an anti-creep bulge 10 of the lower lockpin rod is separated from an anti-creep surface 20 of the coupler shank (as shown in FIG. 1a). At this moment, if the lower lockpin rod is rotated in a coupler unlocking direction, and drives the lower lockpin and the coupler knuckle lock to move upwardly to the unlock position, the coupler will be unlocked. In the case of vibration of car, the lower lockpin rod is moved upwardly and is in the anti-creep position. At this moment, if the lower lockpin rod is rotated towards the coupler unlocking direction, the anti-creep bulge 10 of the lower lockpin rod contacts with the anti-creep surface 20 of the coupler shank (as shown in FIG. 1b) to stop the lower lockpin rod to rotate, thus the coupler can not be unlocked. However, when the car is in running, it is possible that the lower lockpin rod doesn't move upwardly to the anti-creep position but rotates towards the coupler unlocking direction, at this moment, the anti-creep bulge 10 of the lower lockpin rod is moved away from the anti-creep surface 20 of the coupler shank, i.e. the coupler may be unlocked. In view of the above problem, the lower lockpin rod is provided with an anti-creep bolt configured to limit the lower lockpin rod moving upwardly due to vibration, thereby achieving a dual anti-unlocking performance for coupler.
However, for the operating condition with larger load, the anti-creep bolt is easily bended and deformed. For example, during dumping load without unlocking the coupler, the anti-creep bolt is bended and deformed, and thus the coupler knuckle lock is moved out from a coupler knuckle locking surface under gravity. When a traction vehicle draws the car, the coupler knuckle will spontaneously opened, and couplers are separated, which delays the time of dumping load for the whole train and decreases the efficiency in dumping load. In view of the problem, there is an urge demand for an anti-creep mechanism for coupler which has a reliable dual anti-unlocking performance for coupler and avoids accidentally unlocking coupler.